1. Field of the Invention
The present invention relates to a photoreceptor which does not produce abnormal images such as images including light and shade stripes, and images including streaks, which are formed by the multiple reflection of coherent light within the photoreceptor.
The present invention also relates to a method of evaluating the photoreceptor.
The present invention also relates to a method of producing the photoreceptor.
The present invention also relates to an image formation apparatus comprising the photoreceptor, which is capable of producing high quality images free of the light and shade stripes and streaks,
2. Discussion of Background
In recent years, there has been a strong demand for image formation with high precision and high resolution in accordance with the request for highly accurate reproduction of image information.
When image formation is carried out with high resolution, using a photoconductor, in addition to an image to be formed based on an original image information, an image based on the information of the photoconductor itself is apt to be formed.
An image formation process by use of coherent light, such as laser light, as writing light, is widely used in the field of electrophotography for the formation of digital images, for instance, as in copying machines, printers and facsimile apparatus. In an electrophotographic process using coherent light as writing light, a problem is apt to be caused that an image including light and shade stripes (hereinafter referred to as the light and shade striped image) is formed due to the interference of the coherent light within a photoconductive layer of the photoconductor.
It is known that such light and shade stripes are generated by the writing light being intensified when the photoconductor satisfies the relationship of 2nd=mxcex wherein n is the refractive index of a charge transport layer, d is the thickness of the charge transport layer, xcex is the wavelength of the writing light, and m is an integer.
To be more specific, when xcex=780 nm and n=2.0, one set of light and shade stripes appears at each change of 0.195 xcexcm in the thickness of the charge transport layer. In order to remove the light and shade stripes completely, it is necessary to reduce the deviation of the thickness of the charge transport layer to less than 0.195 xcexcm in the entire image formation area. However, it is economically extremely difficult to produce a photoconductor with such a small deviation of the thickness of the charge transport layer as mentioned above, so that various methods have been proposed to control or reduce the formation of the light and shade stripes in the image.
For instance, in Japanese Laid-Open Patent Application 57-165845, there is proposed a photoconductor comprising a support made of aluminum, a charge transport layer formed on the support, a charge generation layer comprising a-Si formed on the charge transport layer, with the provision of a light absorption layer on the aluminum support to remove the mirror reflection of the aluminum support, thereby preventing the formation of the light and shade stripes in images. The provision of the light absorption layer on the aluminum support is extremely effective for preventing the formation of the light and shade stripes in the image with the photoconductor using the charge generation layer comprising a-Si with the layer structure of the aluminum support/charge transport layer/charge generation layer as mentioned above. However, for an organic photoconductor with a layer structure of aluminum support/charge generation layer layer/charge transport layer in general use, the provision of the light absorption layer on the aluminum support is not so effective for preventing the formation of the light and shade stripes in the image.
In Japanese Laid-Open Patent Application 7-295269, there is disclosed a photoconductor with a layer structure of aluminum support/undercoat layer/charge generation layer/charge transport layer, with the provision of a light absorption layer on the aluminum support for preventing the formation of the light and shade stripes in the image. However, the photoconductor with this layer structure cannot completely prevent the formation of the light and shade stripes in the image.
In Japanese Patent Publication 7-27262, there is disclosed an electrophotographic copying apparatus comprising (1) a photoconductor comprising a cylindrical support which has such a convex cross section that is formed by superimposing a sub-peak on a main peak, when the cylindrical support is cut by a plane which includes the axis of the cylindrical support, and (2) an optical system using a coherent light beam with a beam diameter which is less than one period of the main peak for exposure. The support disclosed in Japanese Patent Publication 7-27262 can be produced relatively easily by machining or like.
In some photoconductors, the formation of the light and shade stripes in the image can be controlled to some extent by use of the above-mentioned support. However, many photoconductors cannot prevent the formation of the light and shade stripes in the image even though the above-mentioned support is used.
There is also known a photoconductor with the parameter of the surface roughness of the support thereof being defined, for example, in Japanese Laid-Open Patent Application 10-301311.
When an electrophotographic copying machine to be used with this photoconductor adopts a low resolution, there is the case where the formation of the light and shade striped image can be prevented. However, when an electrophotographic copying machine with high resolution is used, even if the surface roughness of the substrate is defined by conventionally employed parameters such as maximum height, ten-point mean roughness, and center-line mean roughness, there cannot be determined the conditions under which the formation of the light and shade striped image can be completely prevented.
It is also generally known that the state of the formation of the light and shade striped image can be changed by interposing an undercoat layer comprising a white pigment such as titanium oxide between the support and the photoconductive layer. However, the necessary conditions for the undercoat layer to control the formation of the light and shade striped image, such as the thickness of the undercoat layer, largely differ depending upon the surface state of the support, so that the conditions for completely controlling the formation of the light and shade striped image have not been determined.
Although the conditions for removing the light and shade stripes entirely from the image are not completely known, there are many cases where the formation of the light and shade striped image can be reduced by roughening the surface of the support, so that a photoconductor with the surface of the support being finely roughened, produced by machining or like, is often mounted in an image formation apparatus.
Furthermore, it is also known that the formation of the light and shade striped image can be reduced by changing the thickness of the undercoat layer, but its accurate conditions for reducing the formation of the light and shade striped image are not completely known, so that photoconductors are produced under various conditions, and the conditions under which the light and shade striped image is not formed when the photoconductor is mounted and used in the electrophotographic copying machine are determined experimentally. In order to produce a photoconductor which does not form the light and shade striped image, the above experimentally determined production conditions have to be strictly kept. Even when such production conditions are strictly kept, there are many cases where the light and shade stripes appear in the image when the lot, the material and the shape of the photoconductor are changed, so that it is necessary to check and change the production conditions whenever the lot, the material and the shape of the photoconductor are changed.
Even though there are the above-mentioned problems, as long as the resolution of the image formation apparatus low, no big problems occur. However, when an image formation apparatus capable of producing images with high resolution is used, there is a case where apart from the above-mentioned light and shade striped image, an abnormal image including streaks (hereinafter referred to as the streaked image) appears in the entire image. Such streaks are often directed in the circumferential direction of the photoconductor with almost the same intervals between the streaks. Unlike the light and shade striped image, the streaked image appears, not only at the place where the thickness of the photoconductive layer of the photoconductor changes, but also in the area where the thickness of the photoconductive layer is constant, so that the abnormal streaked images often appear in the entire image area.
An investigation has been conducted as to the conditions under which a photoconductor which produces such abnormal streaked images is produced in the course of the continuous production of the photoconductors. As a result, it has been found that the production of such a photoconductor that produces the abnormal streaked images relates to the timing of replacement of a cutting tool used for machining the support of the photoconductor, and that there is a tendency that at the time of replacement of the cutting tool, the photoconductor that produces the abnormal streaked images is apt to be produced. It has also been found that this tendency also depends upon the kind of cutting tool employed. From the above, it can be considered that the state of the surface of the support relates to the production of the streaked images, but it is impossible to define the state of the surface of the support for the photoconductor which does not produce the streaked image by use of the conventionally employed parameters relating to the surface roughness.
For instance, in Japanese Laid-Open Patent Application 7-77817, there is disclosed a method of producing the support for the photoconductor by the steps of transforming a regular arrangement of the surface state of the support to a sine wave function, and transforming a regular arrangement of the lighting period of a writing light to a sine wave function, synthesizing these two sine wave functions to obtain a synthesized sine wave function, determining the period of the synthesized sine wave function, and controlling the machining of the support based on the thus determined period of the synthesized sine wave function. More specifically, in the method disclosed in Japanese Laid-Open Patent Application 7-77817, the support is produced with the period of the sine wave of the support set outside the scope of xc2x15% of the period of the sine wave of the writing light. However, it is extremely difficult to transform a profile of the support to a sine wave, so that a new parameter is necessary to define a profile for producing a photoconductor which does not produce streaked images for use in the image formation apparatus capable of producing images with high resolution.
It is therefore a first object of the present invention to provide a photoreceptor which does not produce abnormal images such as light and shade striped images and streaked images, which are formed by the multiple reflection of coherent light within the photoreceptor.
A second object of the present invention is to provide a method of evaluating the photoreceptor.
A third object of the present invention is to provide a method of producing the photoreceptor.
A fourth object of the present invention is to provide an image formation apparatus comprising the photoreceptor, which is capable of producing high quality images free of the light and shade stripes and the streaks.
The first object of the present invention can be achieved by a photoreceptor comprising a support and a photosensitive layer formed thereon, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexc) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                               S          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              1            N                    ·                                    "LeftBracketingBar"                              X                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            "RightBracketingBar"                        2                                              (        2        )            
I(S) represented by formula (3):                               I          ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        3        )            
is calculated as being 6.0xc3x9710xe2x88x923 or more.
In the present invention, when the photoreceptor is in the shape of a drum as shown in FIG. 1(A), the horizontal direction of the support indicates the direction along the support, which is in parallel to the axis of the photoreceptor drum as indicated by the arrow A as shown in FIG. 1 (A) while when the photoreceptor is in the shape of a rectangular sheet as shown in FIG. 1(B), the horizontal direction of the support indicates the direction along the plane of the support as indicated by the arrow B as shown in FIG. 1(B).
The first object of the present invention can also be achieved by a photoreceptor comprising a support and a photosensitive layer formed thereon, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2),                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
the relationship between the value of nmax, at which   S  ⁢      (          n                        N          ·          Δ                ⁢                  xe2x80x83                ⁢        t              )  
is maximized in the range of n from 1 to N/2, and the pitch Wl (xcexcm) of writing light which is coherent light for image formation is                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                    n        max               greater than           1.05      ⁢              xe2x80x83            ⁢              m        ·                  W          l                    ⁢              xe2x80x83            ⁢      or      ⁢              xe2x80x83            ⁢                                    N            ·            Δ                    ⁢                      xe2x80x83                    ⁢          t                          n          max                       less than           0.95      ⁢              xe2x80x83            ⁢              m        ·                  W          l                      ,
where m is an integer obtained by rounding off the decimals of                     N        ·        Δ            ⁢              xe2x80x83            ⁢      t                      n        max            ·              W        l              ,
provided that when                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                              n          max                ·                  W          l                       less than     1    ,      m    =    1.  
The first object of the present invention can also be achieved by a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile of the surface of the undercoat layer on the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                               S          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              1            N                    ·                                    "LeftBracketingBar"                              X                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            "RightBracketingBar"                        2                                              (        2        )            
I(S) is calculated from formula (4):                                           I            xe2x80x2                    ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        4        )            
as being 6.0xc3x9710xe2x88x923 or more.
The first object of the present invention can also be achieved by a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the surface of the undercoat layer on the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2),                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
the relationship between the value of nmax, at which   S  ⁢      (          n                        N          ·          Δ                ⁢                  xe2x80x83                ⁢        t              )  
is maximized in the range of n from 1 to N/2, and the pitch W, (xcexcm) of writing light which is coherent light for image formation is                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                    n        max               greater than           1.05      ⁢              xe2x80x83            ⁢              m        ·                  W          l                    ⁢              xe2x80x83            ⁢      or      ⁢              xe2x80x83            ⁢                                    N            ·            Δ                    ⁢                      xe2x80x83                    ⁢          t                          n          max                       less than           0.95      ⁢              xe2x80x83            ⁢              m        ·                  W          l                      ,
where m is an integer obtained by rounding off the decimals of                     N        ·        Δ            ⁢              xe2x80x83            ⁢      t                      n        max            ·              W        l              ,
provided that when                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                              n          max                ·                  W          l                       less than     1    ,      m    =    1.  
The first object of the present invention can also be achieved by a photoreceptor comprising a support and a photosensitive layer formed thereon, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile of the surface of the support on the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
Wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
I(S) is calculated from formula (4):                               I          ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        4        )            
as being 12.0xc3x9710xe2x88x923 or more.
The first object of the present invention can also be achieved by a photoreceptor comprising a support and a photosensitive layer formed on the support, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile of the surface of the support on the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2),                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
the relationship between the value of nmax, at which   S  ⁢      (          n                        N          ·          Δ                ⁢                  xe2x80x83                ⁢        t              )  
is maximized in the range of n from 1 to N/2, and the pitch Wl (xcexcm) of writing light which is coherent light for image formation is                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                    n        max               greater than           1.05      ⁢              xe2x80x83            ⁢              m        ·                  W          l                    ⁢              xe2x80x83            ⁢      or      ⁢              xe2x80x83            ⁢                                    N            ·            Δ                    ⁢                      xe2x80x83                    ⁢          t                          n          max                       less than           0.95      ⁢              xe2x80x83            ⁢              m        ·                  W          l                      ,
where m is an integer obtained by rounding off the decimals of                     N        ·        Δ            ⁢              xe2x80x83            ⁢      t                      n        max            ·              W        l              ,
provided that when                               N          ·          Δ                ⁢                  xe2x80x83                ⁢        t                              n          max                ·                  W          l                       less than     1    ,      m    =    1.  
The second object of the present invention can be achieved by a method of evaluating a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed thereon, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
and
comparing a calculated power spectrum with a specific reference, thereby evaluating the photoreceptor.
The second object of the present invention can also be achieved by a method of evaluating a photoreceptor comprising a support and a photosensitive layer formed thereon, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating I(S) represented by formula (4) from the calculated power spectrum,                                           I            ⁡                          (              S              )                                =                                    (                              1                N                            )                        ⁢                                          ∑                                  n                  =                  0                                                  N                  -                  1                                            ⁢                              xe2x80x83                            ⁢                              {                                  S                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  }                                                    ,                            (        4        )            
and
comparing the calculated I(S) with a specific reference, thereby evaluating the photoreceptor.
The second object of the present invention can also be achieved by a method of evaluating a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed thereon, comprising the steps of;
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
Wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2);                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating I(S) represented by formula (4) from the calculated power spectrum,                                           I            ⁡                          (              S              )                                =                                    (                              1                N                            )                        ⁢                                          ∑                                  n                  =                  0                                                  N                  -                  1                                            ⁢                              xe2x80x83                            ⁢                              {                                  S                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  }                                                    ,                            (        4        )            
and
comparing the calculated I(S) with a specific reference, thereby evaluating the photoreceptor.
The second object of the present invention can also be achieved by a method of evaluating a photoreceptor comprising a support and a photosensitive layer formed thereon, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t) (xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating Ixe2x80x2(S) represented by formula (5) from the calculated power spectrum,                                                         I              xe2x80x2                        ⁡                          (              S              )                                =                                    1              N                        ⁢                                          ∑                                  n                  =                  a                                b                            ⁢                              xe2x80x83                            ⁢                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                                                    ,                            (        5        )            
in which a and b each are an integer of N or less, and axe2x89xa6b, and
comparing the calculated Ixe2x80x2(S) with a specific reference, thereby evaluating the photoreceptor.
The second object of the present invention can also be achieved by a method of evaluating a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed thereon, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating Ixe2x80x2(S) represented by formula (5) from the calculated power spectrum,                                                         I              xe2x80x2                        ⁡                          (              S              )                                =                                    1              N                        ⁢                                          ∑                                  n                  =                  a                                b                            ⁢                              xe2x80x83                            ⁢                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                                                    ,                            (        5        )            
in which a and b each are an integer of N or less, and axe2x89xa6b, and
comparing the calculated Ixe2x80x2(S) with a specific reference, thereby evaluating the photoreceptor.
The third object of the present invention can be achieved by a method of producing a photoreceptor comprising a support and a photosensitive layer formed thereon, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
and
comparing a calculated power spectrum with a specific reference, thereby evaluating the photoreceptor.
The third object of the present invention can also be achieved by a method of producing a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the undercoat layer on the side of the photosensitive layer, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
and
comparing a calculated power spectrum with a specific reference, thereby evaluating the photoreceptor.
The third object of the present invention can also be achieved by a method of producing a photoreceptor comprising a support and a photosensitive layer formed thereon, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexc) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1).                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and n are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating I(S) represented by formula (4) from the calculated power spectrum,                                           I            ⁡                          (              S              )                                =                                    (                              1                N                            )                        ⁢                                          ∑                                  n                  =                  0                                                  N                  -                  1                                            ⁢                              xe2x80x83                            ⁢                              {                                  S                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  }                                                    ,                            (        4        )            
and
comparing the calculated I(S) with a specific reference, thereby evaluating the photoreceptor.
The third object of the present invention can also be achieved by a method of producing a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the undercoat layer on the side of the photosensitive layer, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating I(S) represented by formula (4) from the calculated power spectrum,                                           I            ⁡                          (              S              )                                =                                    (                              1                N                            )                        ⁢                                          ∑                                  n                  =                  0                                                  N                  -                  1                                            ⁢                              xe2x80x83                            ⁢                              {                                  S                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  }                                                    ,                            (        4        )            
and
comparing the calculated I(S) with a specific reference, thereby evaluating the photoreceptor.
The third object of the present invention can also be achieved by a method of producing a photoreceptor comprising a support and a photosensitive layer formed thereon, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating Ixe2x80x2(S) represented by formula (5) from the calculated power spectrum,                                                         I              xe2x80x2                        ⁡                          (              S              )                                =                                    1              N                        ⁢                                          ∑                                  n                  =                  a                                b                            ⁢                              xe2x80x83                            ⁢                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                                                    ,                            (        5        )            
in which a and b each are an integer of N or less, and axe2x89xa6b, and
comparing the calculated Ixe2x80x2(S) with a specific reference, thereby evaluating the photoreceptor. The third object of the present invention can also be achieved by a method of producing a photoreceptor comprising a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, by determining the conditions for machining the surface of the photosensitive layer on the side of the support, and/or the surface of the undercoat layer on the side of the photosensitive layer, and/or the surface of the support on the side of the photosensitive layer in accordance with a method of evaluating the photoreceptor, comprising the steps of:
subjecting a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, and/or of a profile at the surface of the undercoat layer on the side of the photoreceptor, and/or of a profile at the surface of the support on the side of the photoreceptor, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer,
calculating a power spectrum in accordance with formula (2);                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
calculating Ixe2x80x2(S) represented by formula (5) from the calculated power spectrum,                                                         I              xe2x80x2                        ⁡                          (              S              )                                =                                    1              N                        ⁢                                          ∑                                  n                  =                  a                                b                            ⁢                              xe2x80x83                            ⁢                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                                                    ,                            (        5        )            
in which a and b each are an integer of N or less, and axe2x89xa6b, and
comparing the calculated Ixe2x80x2(S) with a specific reference, thereby evaluating the photoreceptor.
The fourth object of the present invention can be achieved by an image formation apparatus comprising a photoreceptor which comprises a support and a photosensitive layer formed thereon, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile at the interface of the photosensitive layer on the side of the support, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    i2                                    ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                               S          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              1            N                    ·                                    "LeftBracketingBar"                              X                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            "RightBracketingBar"                        2                                              (        2        )            
I(S) represented by formula (3):                               I          ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        3        )            
is calculated as being 6.0xc3x9710xe2x88x923 or more, in which coherent light is used as writing light for image formation.
The fourth object of the present invention can also be achieved by an image formation apparatus comprising a photoreceptor which comprises a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile of the surface of the undercoat layer on the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                               S          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              1            N                    ·                                    "LeftBracketingBar"                              X                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            "RightBracketingBar"                        2                                              (        2        )            
I(S) is calculated from formula (4):                               I          ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        4        )            
as being 6.0xc3x9710xe2x88x923 or more, in which coherent light is used as writing light for image formation.
The fourth object of the present invention can also be achieved by an image formation apparatus comprising a photoreceptor which comprises a support and a photosensitive layer formed thereon, wherein when a group of data consisting of N samples of the height x(t)(xcexcm) of a profile of the surface of the support an the side of the photosensitive layer, measured perpendicular to the horizontal direction of the support, taken at xcex94t(xcexcm) intervals in the horizontal direction, is subjected to Fourier transformation in accordance with formula (1):                               X          ⁡                      (                          n                                                N                  ·                  Δ                                ⁢                                  xe2x80x83                                ⁢                t                                      )                          =                              ∑                          m              =              0                                      N              -              1                                ⁢                      xe2x80x83                    ⁢                                    x              ⁡                              (                                                      m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                      ⁢                          exp              ⁡                              (                                                      -                    ⅈ                                    ⁢                                      xe2x80x83                                    ⁢                  2                  ⁢                                      xe2x80x83                                    ⁢                                      π                    ·                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              ·                    m                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                )                                                                        (        1        )            
wherein n and m are each an integer, N=2p in which p is an integer, in a power spectrum represented by formula (2):                                           S            ⁡                          (                              n                                                      N                    ·                    Δ                                    ⁢                                      xe2x80x83                                    ⁢                  t                                            )                                =                                    1              N                        ·                                          "LeftBracketingBar"                                  X                  ⁡                                      (                                          n                                                                        N                          ·                          Δ                                                ⁢                                                  xe2x80x83                                                ⁢                        t                                                              )                                                  "RightBracketingBar"                            2                                      ,                            (        2        )            
I(S) is calculated from formula (4):                               I          ⁡                      (            S            )                          =                              (                          1              N                        )                    ⁢                                    ∑                              n                =                0                                            N                -                1                                      ⁢                          xe2x80x83                        ⁢                          {                              S                ⁡                                  (                                      n                                                                  N                        ·                        Δ                                            ⁢                                              xe2x80x83                                            ⁢                      t                                                        )                                            }                                                          (        4        )            
as being 12.0xc3x9710xe2x88x923 or more, in which coherent light is used as writing light for image formation.